Process for the preparation of bicyclo-(3, 2, 1)-octene-(2)



PROCESS FOR THE PREPARATION OF BICYCLO- (3,2,1)-CTENE-(2) Karl HeinzMiiller and Peter Borner, Kamen, Westphalia, Germany, assign ors toSchering Aktiengesellschaft, Berlin, Germany No Drawing. Filed Feb. 11,1963, Ser. No. 257,738 Claims priority, application Germany, Feb. 21,1962,

Sch 31,020 3 Claims. (Cl. 260-666) Ann-0H0 and that it is of advantageto carry out this reaction in the presence of olefins, preferablyalpha-olefins. From the reaction mixture the bicyclo(3,2,tl)-0ctene-(2)is recovered in the manner described hereinafter.

According to a specific modification, instead of the before namedaluminum trialkyl compounds a mixture of 4-vinyl-cyc'lohexene,

CH.=CH(J with other aluminum-alkyl compounds is used, which are capableof forming aluminum trialkyl compounds containing at least one alkylradical of the formula As examples of being used in the process of thisinvention 4-vinylcyclohexene or i-butene are named by way of example.

It could not be expected that the Al-C bonds could be added to thedouble bond of the cyclohexyl ring with the formation of a bicyclicsystem, that this addition takes place in such uniform manner and that,for example, from a cyclo-hexenyl-ethylaluminum compound bicyclo(3,2,-1)-octene-(2) can be obtained.

The preparation of the aluminumtrialkyl compounds having at least onealkyl radical of the formula can be carried out according to methodsknown by themselves. A favorable procedure is, for example, the re-United States Patent 0 "ice action of 4-vinylcyclohexene with suitablealuminumalkyl compounds, particularly aluminum-triisobutyl oraluminum-diiso'butylhydride. Furthermore, as 4-vinylcyclohexene can beeasily obtained by thermal dimerization from 'butadiene, the process ofthis invention creates a possibility of obtainingbicyclo(3,2,l)-octene-(2), with utilization of the petrochemicalbutad-iene which is produced on a large scale.

In carrying out the present invention a commercial scale preferably acontinuous cyclic process can be used. For example, a starting amount ofaluminum-alkyl compounds is reacted in a suitable reactor with4-vinylcyclohexene. The bicyclo-(3,2,l)-octene-2 formed is recoveredfrom the reaction product. The aluminum-alkyl compounds and a rest of4-vinylcyclohexene which eventually has not reacted yet, are likewiseseparated and returned to the process and mixed there with fresh4-vinylcyclohexene, i.e. conducted in a cycle.

The bicyclo(3,2,1,)octene-(2) can be isolated by fractionaldistillation. It is of advantage in this connection to previouslyseparate the C hydrocarbon by vacuum distillation from the highermolecular, eJg. dimerized, products and aluminum alkyl compounds. Fromconcentrated mixtures the bicyclo-(3,2,l)-octene (2) can be recoveredalso by crystallization. After purification by recrystallization andsublimation the product of the invention is a white camphorli-ke masswhich is very volatile and has a melting point, in a sealed tube, of42.5-43.5 C. and a boiling point of B.P. =l35 C. Its index of refractionis n =1.4689.

The reactions with aluminum organic compounds must be carried out inconventional manner with the exclusion of oxygen and humidity.

The bicyclo-(3,2,1)-octene-(2) is of particular utility and importancein the preparation of intermediate products which are capable ofpolymerization and polycondensation.

Example 1 412 g. of 4-vinylcyclohexene are heated to 180 C. togetherwith 226 g.

for 2 hours in a one liter shaking autoclave. The pressure did notexceed 5 atmospheres superatmospheric pressure. After permitting theautoclave to cool, the reaction mixture was transferred to adistillation device provided with a Claisen attachment. Upon stirringand heating up to C. under a pressure of 4 torr, 210 g. of distillatewere collected in the well-cooled receiver. The distillate contained 80%of bicycle-(3,2,l)-octene-(2). The pure Ebicyclo-(3,2,l)-0ctene(2) wasrecovered by fractional distillation 'with an efiicient column.

Example 2 300 g. of 4-vinylcyclohexene and 303 g. of

were introduced into a glass flask provided with a reflux cooler and astirring device. The mixture was heated under reflux until thetemperature reached C. The

Example 3 2511 g. of 4-vinylcyclohexene and 544 g. Al(i-C -H H wereheated in a liter shaking autoclave .for 3 hours to 180 C. The pressurereached thereby about 20 atmospheres of super-atmospheric pressure. Theautoclave was permitted to cool and the reaction mixture was transferredto a distillation apparatus provided with a Claisen attachment. Uponstirring and heating to 110 C., under a pressure of tor-r, 99 8 g.distillate were collected in the well cooled receiver. Subsequently, thedistillate was subjected to distillation with a short tractionatingattachment under atmospheric pressure. Between 130 and 140 C. headtemperature 924 g. of distillate were obtained, which contained 87% of-bicyclo-(3,2,1)- octene-(2) and from which the pure'product wasisolated in the manner described in the above Example 1.

Example 4 and 250 g. i-b-utene were heated in a one liter shakingautoclave for 2 hours to 180 C. After cooling, the excess i-butene wasdischarged and the reaction mixture was transferred into a distillationapparatus provided with a short fractionating attachment. The residuali-butene was removed under vacuum at about 30 torr. Subsequently, understirring heating was carried out up to 110 C. under 5-7 torr. Thereby,96 g. of distillate passed to the cooled receiver. To the distillatewhich contained some aluminum alkyl, carefully some dilute hydrochloricacid was added; it was then shaken, washed with water and dried overpotassium carbonate. 89 g. of a mixture of hydrocarbons containing 46%bicyclo- (3,2,1)-octen-(2) were obtained.

Example 5 are heated in a round-bottomed flask provided with a refluxcooler for 5 hours to 150-180 C. After cooling down of the reactionmass, the yellow, very viscous reaction product is caused to pass at130-140 C. and 01-2 torr through a thin-layer evaporator. Thereby 8 g.of material distilled over and were recovered in a trap cooled with dryCO and acetone. It has been found by means of a gas chromatogram thatthe distillate consisted to about 80% of bicyclo(3,2,1)-octene-2.

The preparation of the compound i Qi from aluminum triisobutyl and4-vinylcyclohexene is described in Metallorganische Verbindungen, XL,Synthesis of Alcohols from Organo-Aluminum Compounds, K. Ziegler, F.Krupp and K. Zosel, Liebigs Annalen der Chemie, 62 9, 241 1960).

The preparation or the compound Aummnmmwm-O-q from aluminum diethylhydrid and 4-vinylcyclo'hexene is described in MetallorganischeVerbindungen, XIX, Reaction or the Aluminum-Hydrogen Bond with Oleiins,

243 g. of

97 g. of

4 K. Ziegler, H. G. Gellert, H. Martin, K. Nagel and J. Schneider,Liebigs Annalen der Chemie, 58 9.

From the a-ole'fius primarily 4-v-inylcyclohexene and i-bu-tene areused. Bicyclo-(3,2,l)-octene-2 is formed also in the presence ofmixtures of ot-OlClfiIJS, such as propene and 4vinyl-cyclohexene andalso butene-l and 4-vinylcyclohexene.

Purification of the bicyclo-(3, 2,l)-2-o'ctene was carried out (fromhighly concentrated, but still liquid (or remelted) crude product.

It has been known that bicyclo-(3,2,l)-octene-2 can be converted overbicyclooctanol, and over the bicyclooctanon into thecyclopentane-(1)-cauboxylic acid-3- acetic acid. This dicauboxylic acidcan be condensed with dioles or diamines to polyesters or polyamideswhich can be used as thermoplastic materials.

The temperature of the reaction is carried out in the range or l30-350C. and under a pressure in the range between 1 atmosphere up to thepressure which corresponds to the vapor tension of the reaction mixtureat the reaction temperature used.

The lower limit for the proportions of olefin and aluminum compound isat 1:01. In the example 5, the upper limit is stated with an aluminumcompound without olefin-reactant.

What is claimed is:

1. A process for the preparation of bicyclo-(3,2,1)- octene-(Z) CH: CH

CHr-CHCH5 comprising heating aluminum trialkyl compounds, in which atleast one alkyl radical is and the rest of the alkyl radicals isselected from the group consisting of and lower alkyl radicals, to atemperature in the range of C. to 350 C. and separating the bicyclo-(3,2,1)- octene (2) from the reaction mixture, the aluminum trialkylcompound being heated together with i butene.

2. A process for the preparation of bicyclo-(3,2,l)- octene-(Z)CHz(lJH(3H (1H2 CH CHzCH-CH2 comprising heating aluminum trialkylcompounds, in which at least one alkyl radical is and the rest of thealkyl radicals is selected from the group consisting of and lower alkylradicals, to a temperature in the range of 130 C. to 350 C. andseparating the bicyclo(3,2,l)- octene-(2) from the reaction mixture, thealuminum trialkyl compound being heated together with an alphaolefin.

3. A process for the preparation of bicyclo-(3,2,1)- octene-(2) Gm-(JHAEH (3H1 CH CHPCH-(IJHZ comprising heating aluminum trialkylcompounds, in alkyl compound being heated together with4-viny1cyclowhich at least one alkyl radical is hexene.

CH2CH2 References Cited by the Examiner and the rest of the alkylradicals is selected from the UNITED STATES PATENTS group consisting of2,826,598 3/ 1958 Ziegler et a1 260666 CHZCH2O DELB'ERT E. GANTZ,Primary Examiner.

and lower alkyl radicals, to a temperature in the range 10 LEONARDFORMAN Examiner of 130 C. to 350 C. and separating the bicyclo-(3,2,1)-V. OKEEFE, Assistant Examiner. octene-(2) from the reaction mixture, thealuminum tri-

2. A PROCESS FOR THE PREPARATION OF BICYCLO-(3,2,1)OCTENE- (2) 